US2366743A - Treatment of hydrocarbon materials - Google Patents

Description

Jan., 9 1945 l M. P. MATUszAK 2,365,743

l I TREATMENT OF HYDROCARBON MATERIALS Filed May rees, 1941 N ff) QNILOVLNOD O y W Q o Z n q, 39 g1 N LLU II gf 55E Ld Q 2li INVENTOR 92 MARYAN RKMATUSZAK I bons.v

Patented mlan @9 i945 l U l;

rattan TREATMENT GF HYDRCARBON MATERIALS Mlaryan P. Matuszak, Bartlesville, Okla., assignor Y to Phillips Petroleum Company, a corporation of Delaware Application May Z6, 19M, Serial No. 395,280

I 4 Claims.

This invention relates to the treatment of hydrocarbon materials and more particularly to the treatment of hydrocarbon materials containing relatively unsaturated hydrocarbons under such conditions as to remove substantially all of the unsaturated hydrocarbons contained therein. It relates particularly to the removal of aliphatic unsaturated compounds from relatively low-boiling hydrocarbon fractions.

Heretofore, hydrocarbon materials containing unsaturated hydrocarbons have been treated with sulfuric acid inorder to remove said unsaturated hydrocarbons. In many cases this treatment is only partially successful due apparently to the oxidizing effect of the acid on the unsaturated constituents of the oil. This is especially true when concentrated sulfuric acid is used for the treatment. 'I'he oxidizing effect is of ysuch a nature lthat substances are pro duced in the main body of the hydrocarbon material which bring about an unstablecondition in the material with respect to color4 and odor.

Furthermore, it has been proposed to associate sulfuric acid with boric acid, phosphoric acid, nitric acid or acetic acid to remove certain undesirable material from mixtures of hydrocar-4 Also, undesirable material has been removed from mixtures of hydrocarbons by treating the mixtures with either nitric acid, acetic acid, phosphoric acid or maleic anhydride alone or mixtures of hydrochloric acid and ores of l certain metals. In many of these instances the material so removed-comprises diolens, objectionable color-forming. odor-forming, sulfur and/or analogous constituents objectionable for inclusion in motor fuel and does not include mono-oleiins.

I have now found that a hydrocarbon material can be freed of substantially all its content of unsaturated hydrocarbons, particularly when the unsaturated hydrocarbons are aliphatic and cyclic, nonaromatic unsaturated hydrocarbons and their derivatives, such as olefins, diolens, cycloolens, and derivatives such as styrene, by treating these hydrocarbon materials with substantial amounts of hydrofluoric acid. 4I have also found that, in connection with such treatments, hydrofluoric acid which tends to remain in the treated hydrocarbon material can be removed by a physical treatment more particularly to be described.

An object of this invention is to remove unsaturated hydrocarbons from certain hydrocarbon materials.-

Another object of this invention is to remove unsaturated hydrocarbons from normally gaseous and/or normally liquid hydrocarbons by the use ofa treating material and thereby produce a substantially saturated hydrocarbon product free from the treating material and freefrorn unsaturated hydrocarbons.

A further object is to provide a process for treating hydrocarbon materials whereby oxidizable, polymerizable, gum-forming, and colorforming constituents are removed.

Further objects and advantages of this inven tion will become apparent from the accompanying disclosure and discussion.

These objects may `be accomplished in accordance with my-invention by treating hydrocarbon materials normally gaseous and/or normally liquid and .in either gaseous or liquid phase with hydrofluoric acid at ordinary temperatures and in suflicient'amount to remove substantially all unsaturated.' hydrocarbons. As a modication this treating operation maybe cooperatively combined in my invention with a separation step wherein hydrofluoric acid is removed from the product in a novel manner, involving distillation.

The hydrocarbon materials and the hydrofluoric acid are preferably in the liquid phase `although the application of my process is not limited to treating only in liquid phase, as in some instances, especially with a C4 hydrocar' bon fraction or similar low-boiling fraction, the hydrocarbon material may be partially or en tirely in the vaporl phase. Although I prefer to employ substantially anhydrous lhydroluoric acid or hydrogen iluoride as treating material in my process, at times I may advantageously treat hydrocarbon material containing unsaturated hydrocarbons with acid containing small amounts of diluent material, especially Water; so that the concentration of the hydrofluoric acid in the treating material may range between about and 100 per cent acid by'weight.

The amount of hydroiiuoric acid originally used should be suiiicient to form a distinct and appreciable liquid phase containing a major proportion of hydrofluoric acid under the conditions of treatment and, preferably, is several times this amount. nature of the hydrocarbon material treated, and particularly with the content of relatively unsaturated hydrocarbons. The amount of hydrouoric acid for treating generally should not be less than that required to produce' a substantially saturated hydrocarbon material. An amount of hydrofluoric acid equal to or several The amount will vary with the' times greater than the hydrocarbon material to be treated may be set asapproximately the maximum that may need to be used. However, an amount between l and 50 per cent by volume of the hydrocarbon material will generally be found satisfactory.

Hydrocarbon materials consisting predominantly or entirely ofv unsaturated hydrocarbons are generally not satisfactorily treated by the present process, although, ifl for some reason it appears. desirable to treat such materials with hydrofiuoric acid, for example, to remove part or all of the unsaturated hydrocarbons, this treatment is entirely within the spirit of the invention. Furthermore, when unsaturated hydrocarbons are the predominant hydrocarbon materials comprising a mixture containing nonhydrocarbon constituents substantially inert to and insoluble in hydroiiuoric acid under the prevailing conditions, my invention will 'find particular application for removing substantially all of the unsaturated hydrocarbons therefrom The mutual solubility of liquid hydrocarbons and of liquid hydrouoric acid increases appreciably with increase in temperature, and this will need to be taken into consideration in establishing the treating conditions in any particular case.

Treatment with hydroiiuoric acid of hydrocarbon material containing unsaturated hydrocarbons may, for certain individual cases be con-v ducted, however, at temperatures ranging from about -100 to about 300 F. although in most cases prefer to' operate between about 0 and 150 F. The pressure should be suiiicient to insure proper flow through the apparatus, and when liquid phase operation is desired should be such to insure this at the temperature of operation.

3In the treatment of normally liquid hydrocarbon material, 'such as motor fuels, kerosenes, fuel oils, Diesel oils, and lubricating oils, and the like, containing unsaturated hydrocarbons, al relatively low-boiling liquefied fparaftln, such as propane or ka butane, preferably normal butane, or

a mixture of relatively low-boiling liqueed paraflins, can be added to the normally liquid hydro-l carbon material before, during, or after contacting said material with hydrofiuoric acid. This low-boiling hydrocarbon material so added aids in subsequent removal of residual hydrogen iluoride which will remain. dissolved in the hydrocarbon phase after physical separation of the major part ofthe hydrofluoric acid phase.

In a preferred manner of operating, a normally liquid hydrocarbon material is treated with hydroiluoric acid, an acid phase separated from i a hydrocarbon phase 'containing normally liquid hydrocarbons and dissolved hydrofiuoric acid, after which a low-boiling liquefied paraiiin or mixture of such parafns is added to said hydrocarbon phase. This is often preferably to having a low-boiling parain hydrocarbon present when an acid phase is also present in the treatment of normally liquid hydrocarbon. In either case the hydrocarbon phase is fractionally distilled to remove a low-boiling fraction in which the distilled low-boiling paraiiin hydrocarbon carries with it, as a part of the low-boiling mixture, hy-

droi'luoric acid which formerly had been dissolved in the normally liquid hydrocarbon phase. Such low-boiling hydrocarbons form minimum-boiling azeotropic mixtures with hydrofluoric acid, and with theproper conditions the overhead fraction will be such an azeotropic mixture. Howassegna ever, in actual plant operations such close control will often not be feasible, although the process will have taken advantage of this characteristic. Such treatment Aeffects removal of hydroiiuoric acid from the normally liquid hydrocarbon phase without the loss of this material that would occur ii the 4removal were made by water-washing, alkali-washing, or the like and without the same increase in temperature that would be necessary torl removal of the acid by simple fractional distillation. However, simple fractional distillation of the dissolved hydrofluorlc acid from the treated liquid hydrocarbon material, without prior addition of a relatively low-boiling paraiiin, may be practiced. The acid removed by either type of fractional distillation is suitable for re-use in the treatment of additional hydrocarbon material. A

The invention will now be described in connection with the accompanying drawing, which forms a part of this specification and illustrates diagrammatically an arrangement of apparatus for carrying out my process, the description serving to exemplify the invention.

A charge stools comprising a hydrocarbon materiai which contains undesired unsaturated hydrocarbons is admitted through conduit It controlled'by valve ii to a contacting chamber E2 wherein it is thoroughly contacted with liquid hydrofluoric acid. The hydrocarbon material enters chamber i2 preferably in the liquid phase and the pressure and temperature maintained in chamber I2 are such that the constituents are substantially in the iiquid phase at all times, although it is well within the spirit of my invention to contact a low-boiling hydrocarbon material in the gas or vapor phase with hydroiiuoric acid inthe liquid phase. Hydroluoric acid is admitted to the apparatus. through conduit I3 controlled by valve It to chamber i2 and inthe liquid phase is dispersed in'chamber I2. The

contacting of the acid and hydrocarbon material may be batchwlse or continuous, and may be concurrent effected by any of several well-known mixing devices, such as efficient stirring mechanisms, turbulence chambers, etc., but itis preferably continuous and countercurrent, so that fresh acid comes inl contact with hydrocarbon material that has already lost most of its vcontent of relatively' unsaturated hydrocarbons, in a. manner known to the art. Sumcient hydroilu" oric acid is admitted to chamber i2 s'o that under preferred conditionsof operation a liquid phasel 4containing a major portion of hydrofluoric acid and aminor portion of hydrocarbon and another 1 liquid phase containing a. major portion of-hydrocarbons and a minor portion of hydrofluoric acid areA present therein. Ordinary temperatures or slightly below or, above ordinary temperatures such as between 0 and 150 1i'. can be maintained in chamber I2.

A hydroiiuoric acid phase containing material stream may be removed from the system througl'f conduit 25 controlled by valve 26 which connects with conduit i3. Undesired organic material from which this hydroiiuoric acidhas been sepa-` uct of the process through conduit 3ft controlled by a valve 35. A low-boilingfraction containing hydrouoric acid is removed through conduit 35 and may be returned to the contacting chamber for further use in the process through valves 3l and 3B to conduit l0.

If desired it may be introduced at an intermediate point of the contacting chamber as by being passed through conduit lili and valve 4l from conduit 36. Any portion or all of the material passing through conduit 36 may be removed from the system through conduit i2 controlled by valve 39.

When the hydrocarbon material treated in the process is normally liquid and contains substan-v tially no or only small amounts of low-.boiling hydrocarbons: such as propane, butane, or pentane, it is founddesirable to conduct the distillation in fractionating means 33 in the presence of an amount of such a low-boiling hydrocarbon as will forman azeotropic mixture' with the hydrofiuoric acid and thereby promote its separation from the puried hydrocarbon product. An amount of low-boiling hydrocarbon suiiicient to have this effe-ct and preferably an amount of such low-boiling hydrocarbon somewhat in excess of the exact amount required to form such an azeotropic mixture should be introduced into the fractionating means. Such a lowboiling parafn can be introduced to the system through conduit ld controlled by a valve t5, may be passed directly through a valve i3 to conduit 3ll or may be introduced at an. intermediate point in fractionating means 33 as through conduit li controlled bya valve lll. With this method of operation a low-boiling fraction removed through conduit 3E will contain a substantial proportion or all of such low-boiling parafiin hydrocarbons which may be recycled Within the system as described. In some instances it may bedesired to 'effect a separation between the hydrocarbon and hydrofluoric acid constituents from the material passing through conduit 36 in which case any part or all of this stream may be passed through conduit t2 controlled by valve t3 to separating means 556. In separation means 56 a hydrofiuoric acid fraction, separated in a desired manner, may be removed therefrom through conduit t3 controlled by a 'valve 6l and returned to the system by being passed through conduitl I3. Any desired part of this stream may be removed from the system through conduit m controlled by valve il. A suitable low-boiling parafiin fraction may be removed from separating means E6 and returned to the system through conduit 'controlled by a valve B which leads to conduit M. At times it may be found that the presence of a low-boiling paraffin material in the contacting chamber l2 will aid the separation of hydrofluoric acid and hydrocarbon phases in this conseparation of hydroluoric acid dissolved in the hydrocarbon stream passing through conduit 3U may be eected byA cooling this stream to atmospheric or subatmospheric temperature. In this case any desired portion of the stream may be passed from conduit ill through conduit 5l! controlled by a valve 5l, cooled in cooler 52 to a desired separation temperature, preferably between 10 and 50 F., and

passedthrough conduit 53 to a separator 55. In

separator 55 aseparation will take place at this lower temperature between a liquid hydroiiuoric acid phase and a hydrocarbon phase. The hydrofluoric acid phase may be passed from separator 55 through conduit 5E controlled by a valve 5l to conduit l5 for subsequent treatment in separating means 2l] as described. If desired, any part or all of this stream may be discharged from the systeml from conduit 58 controlled by a valve 59. Separator 55 will also be used when the contacting chamber is operated in aconcurrent manner rather than the countercurrent system specically shown or when batch operation is employed. The

hydrocarbon phase is passed from separator through conduit Eli controlled by a valve 5l .back to conduit 3U for subsequent treatment in the system as herein discussed. 4

While the particular separation system carried out with fractional distillation in the presence of a low-boiling parai'ln forms a distinct modication of the invention, I do not wish to be restricted to this specific modiiicationin all cases, and may effect a separation of the hydrofluoric acid dis-- solved in the hydrocarbon stream passing through conduit 30 in any manner which maybe convenient or' known to the art as by washing this material with water or an alkaline aqueous solution.

Such other separation may be carried out in sel)- arating means 66 in which case the puried hydrocarbon material is passed from conduit 3l! through conduit 'i2 controlled by a valve T3 to separating means Gli and a purified hydrocarbon product is recovered through conduit Hl con- -V trolled by a valvel'l5.

My invention will more generally be carried out in connection with the removal of unsaturated hydrocarbons from low-boiling hydrocarbon fractions such as gasoline or kerosene or the like, although as discussed it may alsov be applied to fractions vvhich are higher-boiling or lower-boiling than such stocks. The purification in contacting chamber l2 will preferably be carried out in a liquid phase although when low-boiling stocks such as the C4 fraction from a cracking still or the like is'being treated it may at times be round desirable to have the hydrocarbon material in vapor phase. In connection with the purification of a liquid stock together witha separation of the dissolved hydrouoric acid from the purified material in fractionating means 33, an initial amount of low-boiling parains such as normal butane may be added through conduit 'M at the start of the process after which this low boiling parain may be recycled within the system as discussed with further additions of low-boiling paraln being made only for the purpose of compensating for unavoidable losses. When the hydrocarbon material charged through contains such a low-boiling paraffin it may be unpreviously conduit I0 necessary to add additional material through conduit 44 and after a steady state of separation has been reached with suitable recyclewith the low-boiling parailln removed through conduit 36, the puried hydrocarbon product recovered through conduit 34 will contain substantially the same amount as was contained in the material charged through conduit it.

It willof course, be appreciated that the drawing is diagrammatic and does not show in detail many pieces of equipment such as pumps, heat exchangers, heating coils, cooling coils, reflux lines, and the like which are well known to the art and which normally form a part of the various pieces of equipment shown diagrammatically.

. When employing fractionating means 33 this can be :a single fractionating column with ordinary bubble plates or other internal construction assuma cient amount to produce a liquid phase containing a major portion ofthe hydroiluoric acid, passing a mixture of hydrocarbon material and hydro-` relatively low-boiling paranic material, passing known to the art with suitable means for providing a liquid rei-lux. `Although it will generally -not be necessary, fractionating means 33 may comprise two or more fractional distillation columns in some particular instances. The exact equipmentito be installed and conditions for its operation for any particular use of my invention may be readily ascertained by one skilled in the art in the light of the accompanying disclosure and discussion. y

In order to more clearly illustrate my invention and the desirable Aresults obtained thereby, the following examples are given. The conditions given therein exemplify the invention, but are not necessarily to be used to limit the invention.'

Example I An alkylate obtained by the sulfuric acid alkylation of isobutane with a refinery cut containing a substantial proportion of gaseous olens, mainly normal butylenes, is treatedy with about a fifth of its4 own volume of liquid hydroluoric acid. The treated alkylate, after separa-'- tion and withdrawal of the acidphase, is washed acid-free with Water.. The olefin content of the alkylate decreases from an'original value of about 1.5 per cent to so' small a value that it cannot be measured by titration of a sample with a dilute solution of bromine in carbon tetrachloride.

.Example II A motor fuel comprising chiefly loctanes but r containing 0.8 to 1.0 per cent of octe'nes that escaped'hydrogenation in a preceding hydrogenation step is mixed with about a tenth of its own volume of liquefied normal butane and about the same amount of liquid hydrofiuoric acid. After a thorough mixing, the mixture is cooled to about 40 F.; the acid is allowed to separate and is withdrawn. The hydrocarbon mixture is fractionally distilled to remove'the added butane and the dis-v solved hydroiluoric acid. 'I'he residual motor fuel is free from hydrofluoric acid and is free from olefinic hydrocarbons.

The acid phase which is separated and withdrawn from a hydrocarbon phase is subjectedto fractional distillation whereupon hydroi'luoric` acid is separated from unsaturated hydrocarbons. The hydrofluoric acid is recovered and in a con 4tinuous process is mixed with incoming hydrocarbon charge stock.

What is claimed is:

l. A process of treating a hydrocarbon material containing normally liquid hydrocarbons and unsaturated hydrocarbons, whichv comprises contacting such hydrocarbon material with liquid hydroiluoric acid in a. contacting chamber and in sulthis admixture to a fractional distillation means and separating therefrom a'low-boiling fraction containing low-boiling .paraliinic hydrocarbon material and hydrouoric acid, 4separating alsoa fraction containing saturated-normally Iliquid hydrocarbon material substantially free from unsaturated hydrocarbons and hydrouoric acid and removing the saturated normally liquid hydrocarbon material from the process.

2. A proc ss of treating a hydrocarbon material containing normally liquid hydrocarbons and unsaturated hydrocarbons, which comprises admixing such hydrocarbon material with substantially anhydrous hydrouoric acid in a contacting chamber, passing a resulting hydrocarbon-containing mixture to a separating means, removing therefrom a. liquid phase containing normally liquid substantially saturated hydrocarbons and dissolved hydrofluoric acid, admixing with the liquid phase a relatively low-boiling paraffinic material, passing the liquid phase and relatively low-V .boiling parafflnic material toa fractional distillation means, separating from said distillation.

means a low-boiling fraction containing at least a portion of the low-boiling paraiilnic material and substantially all of the dissolved hydroiluoric acid, passing said fraction to a treating means from which hydrouoric acid is removed, circulat. ing said hydroiiuoric acid to the contacting chamber, separating also from the fractional distillation vmeans a higher boiling fraction containing saturated normally liquid hydrocarbons substan-q tially free from unsaturated hydrocarbons and hydrofluoric acid,land removing said higher boiling fraction from the process.

3. A process of treating a hydrocarbon material containing normally liquid hydrocarbons and unsaturated hydrocarbons, which comprises admixing such hydrocarbon material with substantially anhydrous hydrofluoric acid in a contacting low boiling paralnic material to a fractional disvtillation means, separating from said distillation means a low boiling fraction containing at least 4 saturated normally liquid hydrocarbons free from unsaturated hydrocarbons and hydroiiuoric acid, and removing said higher boiling fraction from the process. /f/f 4. A process of treating a hydrocarbon material containing at least some unsaturated hydrocarbons, which comprises contactingl the hydrocarbon material with liquid hydrofluoric acid in a contacting chamber and in sunlcient amount to form a liquid phase containing a major portion of the hydrofiuoric acid and a liquid phase containing a mixture of the hydrocarbon materials and the remaining hydrofluoric acid, passing said mixture of hydrocarbon material and remaining hydrofluoric acid to a first separating means, removing therefrom a. liquid phase containing hydrouoric acid and passing saidphase along with the liquid phase containing a major portion of the hydroiluoric lacid to a second -separating means wherein hydroiiuoric acid suitable for reuse in the treatment of additional hydrocarbon material is separated and returned to the contacting chamber; removing also from the iirst separating means a second phase' containing substantially saturated hydrocarbons and dissolvedY hydrofluoric acid, admixing with this second phase a relatively low boiling paraiiinic material in an amount at least suiiicient to form an azeotropic mixture with said dissolved hydroiiuoric acid, passing this second phase with admixed low boiling paramnic material to a fractional distillation means, separating therefrom a low boiling frac;- tion containing at least a portion of the low boiling paralnic material and substantially all of the dissolved hydrouoric acid, passing said fraction to a treating means from which hydrofluoric acid is removed and circulating said hydroiiuoric acid to the contacting chamber, and separating from the treating means the low boiling paraiiinic material and recirculating this material to the fractional distillation means, and separating also from the treating means andfrom the fractional distillation means higher boiling fractions containing saturated normally liquid hydrocarbons Afree from unsaturated hydrocarbons and hydrouoric acid, and removing. said saturated hydrocarbon fractions from 'the process.

MARYAN P. MATUSZAK.

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